Plastic debris - problems and solutions

Plastic debris now litters the globe from the deep sea to some of the highest mountains. Millions of tonnes of plastic items are now present in the marine environment, most are buoyant and are accumulating at the sea surface or are washed up on the shore. From the poles to the equator, it is now hard to walk along even the remotest shorelines without encountering plastic debris.

Within just a few decades plastics have become part of daily life for almost all of us. They are durable, lightweight, versatile and inexpensive. A pen, a phone, a television, a toothbrush, a steering wheel, a seat cover, an item of clothing - these and other plastic objects are almost always within an arm's reach.

As a consequence of their increased mass production in the past 50 years, plastic usage has increased exponentially. Worldwide production has grown from around five million tonnes per year in the 1950s to over 100 million tonnes today, and the diversity of plastic products is so extensive that it seems almost impossible to imagine life without them. Once used, a large proportion of the resultant debris will go to landfill, some will be recycled or reused, but a significant amount will be discarded into the environment. We still know relatively little about the longevity of this debris. Some estimates suggest plastics will last for hundreds of years while others indicate that thousands of years is a more appropriate timescale. However, we do know that durability, coupled with increasing levels of global production, presents a major waste management problem.

The accumulation of plastic debris in the marine environment has been well documented and the frequency of accounts has increased markedly since the early 1970s. Plastic is accumulating in the oceans, floating at the surface and on the seabed. Prevailing winds and ocean currents redistribute and concentrate this debris to such an extent that some areas of the Pacific are reported to have in excess of 300,000 items of plastic per square kilometer, while some beaches have over 10,000 items of small plastic debris per square meter. Even the deep sea is now strewn with plastic debris that has lost its original buoyancy because of the steady accumulation of marine organisms colonising its surface.

More concerning are the challenges that plastic debris presents to marine life, causing feeding deficiencies, suffocation and death. A wide range of creatures mistake plastic debris for food: to a turtle, for instance, a floating plastic bag may appear strikingly similar to the jellyfish it would typically eat. Over 80 species of sea birds, 26 species of marine mammals, including whales and manatees, and numerous fish species are known to mistake small items of plastic for their prey. Such encounters with plastic obstruct the digestive tract, reducing the capability for further feeding. Unlike natural prey, plastics are resistant to digestion and can remain within the guts of marine creatures. Recently, it has been shown that over 95% of fulmars washed up dead on beaches in the North Sea had plastic in their guts. As well as problems derived from eating plastics, fish, birds and marine mammals frequently become entangled in plastic twine, rope and netting, invariably leading to severe injures or death.

Recently, work at the University of Plymouth has shown that microscopic fragments of plastic have also accumulated in the oceans over the past 40 years. These fragments, many smaller than the diameter of a human hair, are now common in the water column and in marine sediments around the British Isles. These fragments are likely to have formed by the mechanical and chemical breakdown of larger items and owing to their size, these particles could potentially be eaten by a wide range of organisms. However, the environmental consequences of this microplastic debris are only just becoming apparent.

What can be done? Despite the scale of the problem this is an issue we can all help redress. The majority of plastic debris enters the sea as a consequence of careless disposal of everyday objects, so unlike some chemical contaminants that can seep insidiously into the environment in water-borne discharges, most plastic debris is accumulating as a consequence of irresponsible littering by all of us. The most significant step in reducing marine contamination is to dispose of our litter properly. Furthermore, we can all reduce our use of disposable plastic products. Manufacturers and suppliers can help by using the minimum amount of packaging required to get goods safely to their customers. There is also a need for initiatives to make recycling of plastics easier and more complete. Working together as consumers, suppliers, manufacturers, scientific advisors and legislators, there are solutions, but we must act on this as a priority.

Dr Richard Thompson
Reader in Marine Ecology
University of Plymouth, UK


To find out what you can do to help, buy the Blue Frontier Campaign's book, "50 Ways to Save the Ocean". To read the chapter on plastic pollution, click here.